What are the potential safety hazards of MRI, and how are they avoided?
The greatest safety hazard of MRI is related to the very powerful magnet within the scanner. Any ferromagnetic materials within the scanner room have the potential to become projectiles and become attached to the outer housing of the scanner or embedded in the scanner bore. This applies to nonmedical objects (e.g., keys, jewelry/piercings, watches, hair accessories, hearing aids, pagers/mobile phones, computers, scissors, weapons, etc.) as well as equipment commonly found in the hospital (e.g., wheelchairs, stretchers, oxygen canisters, laryngoscopes, etc.). If this occurs while a patient is on the scanner table, drastic—even fatal—consequences may result. For this reason, patients are screened for ferromagnetic materials before entering the MRI scanner room, and medical staff are required to complete MRI safety training before being allowed to enter the scanner room. In addition, there are a number of contraindications to MRI.